Protective duct for fire-detecting conductors.



C. A. HARSCH.

PROTECTIVE DUCT FOR FIRE DETECTING CONDUCTORS. APPLICATION FILED APR.11. 1914.

1,142,094. I Patented Jun e 8,1915.

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UNITED. sTAtrEs QFFIGE.

CHARLES A. HARSCH, OF NEW YORK, N. Y., ASSIGNOZB, IESNE ASSIGNMENTS, TO

THE FIRE DETECTING WIRE COMPANY, (INCH) 0? NEW YORK, N. Y., A COBI'OBA-TION 035 NEW' YORK.

PROTECTIVE DUCT FOB FIRE-DETECTING CONDUCTORS.

Specification of Letters Patent.

Patented June 8, 1915'.

Application filed April 11, 1914. Serial No. 831,266.

To all whom it may concern:

Be it known that I, CHARLES AUGUST HAnsoH, a citizen of the UnitedStates, residing in the city of New York, borough of the Bronx, State ofNew York, have made certain new and useful Improvements in ProtectiveDucts for Fire-Detecting Conductors, of which the following is aspecification.

This invention relates to ducts for insulated electric conductors,separated by an easily fusible layer. 1

The object of the invention is to provide mechanical protection forelectric conductors arranged in pairs, insulated from each other, andseparated by an easily fusible metal, so that when heat is applied to apredetermined degree the fusible metal melts, expands, penetrates theinsulation separating the conductors, and makes electrical connectionbetween them.

Before my invention such conductors had been openly supported on thewall at or near the floor line and also at or near the ceiling, but inuse they were liable to mechanical injury. To avoid this I provide aconduit or molding of heat conducting material such as sheet metalhaving thin walls, and these walls are perforated so that the heat hasaccess to the insulated conductor directly throughthe holes in themolding and also by conduction and radiation through the metal wall ofthe duct.

The drawings illustrate the invention.

Figure 1 shows a form of duct suitable for attachment to a wall, eitherat the base board or at any point; the duct 0?, is made of sheet metalof high heat conductivity and is provided with perforations p; duct a?has a flange a with perforations s to receive screws or nails to attachit to the wall or base board; the perforations ;0 are shown in the frontsurface of the duct but it may be found more advantageous to provideperforations p on the lower side of the duct, as shown in the crosssection Fig. 10. The cross section Fig. 2 shows the detail of Fig. lwith fire detecting twin conductors c, in position.

The conductors 0, so arranged, are well known, composed of a core wire10, having a fusible metal coating 11, of extremely low on the floor orwhere there is unusual liability to mechanical injury; this showselongated perforations. In Figs. 7 and 8 I have shown the same duct withthe round perforations p. In Figs. 9 and 10 I have shown the duct asformed for use as apieture molding; the duct has perforations g1) on itsunder surface and these may be either round or elongated, as alreadyshown. The duct and the flange are made integral, of thin sheet metal,preferably of high heat conductivity. Both walls of the flange a areperforated at s as shown in Fig. 10. It has been found that thisarrangement of duct has many features of merit; theduct is exposed toview; heated air raises the temperature of the sheet metal, the ductradiates heat internally, the heated air also affects the conductorsdirectly, through the perforations, while the heated duct tends toprotect the conductor from any cooling action due to occasional currentsof air, at normal atmospheric temperature.

\\ What I claim is:

1. A duct formed of a material having high heat conductivity with asupporting flange, said duct and flange being in the form of a picturemolding, in combination with a pair of insulated conductors fixed inclose proximity with an intervening layer of metal having a low fusingpoint said conductor being located within said duct close to a series ofperforations in said duct.

2. The combination of a duct formed of sheet metal having a high degreeof heat conductivity, provided with a series of perforations in itsexposed wall affording free access for air, and a pair of electricconductors located within said duct, said conductors being in closeproximity, separated by a thin layer of insulating material and a thinlayer of metal having a low fusing point.

3. The combination of a duct of sheet metal having a flange adapted forattachment to a support, said duct having perforations inits nemzepea.

ex osed surface edaptedte admit heated air said fusible material andsaid insulating to its interior, and e fire detecting conductormateriel,

iocated Within said duct and prptected there-= by, said conductor havingan insulating me- CHARLES HARSGH' 3 terial and a material fusible at alow tem- Witnesses? peratu 'e, and'a complementary conductor W. B.VANSIGL separated from the first-named conductor by. OHN. M; NUGENT.

